YAROSLAVL, Russia (AP) ' President Dmitry Medvedev called for immediate changes in Russia's troubled aviation industry Thursday ' including sharply reducing the number of airlines ' as the country mourned a crash that killed 43 people and devastated a top ice hockey team.

The crash Wednesday killed 36 players, coaches and staff of the Lokomotiv Yaroslavl team, including European and former NHL players, drawing new attention to the poor air safety records of Russia and other former Soviet republics.

Experts blame the problems on an aging fleet, weak government controls, poor pilot training and a cost-cutting mentality.

Investigators could not immediately pinpoint what caused the Yak-42 jet to crash into the banks of the Volga River shortly after takeoff from Yaroslavl, 150 miles (240 kilometers) northeast of Moscow. Workers labored Thursday to raise the plane's shattered tail section, site of one of the plane's on-board recorders.

The two crash survivors ' player Alexander Galimov and crew member Alexander Sizov ' were both reported to be in grave condition Thursday after being flown to Moscow for treatment.

The plane crashed on the opening day of an international forum that was to showcase Yaroslavl as a modern and vibrant Russian city. Medvedev laid flowers at the crash site Thursday and met with officials, and then opened his speech at the forum by calling for a moment of silence the victims.

"The number of air companies should be radically reduced and it's necessary to do this within the shortest time," Medvedev told the conference. Experts say smaller carriers sometimes lack funds to properly maintain their fleet and tend to cut corners on safety.

The crashed jet was built in 1993 and one of its three engines was replaced a month ago, Deputy Transport Minister Valery Okulov said. It is unclear whether technical failures played a role in the crash, but the plane apparently struggled to gain altitude and then hit a signal tower before breaking apart along the Volga.

Okulov said federal transportation authorities are considering whether to halt flights by the 57 Yak-42s still in service in Russia, the state news agency RIA Novosti reported.

Some hockey fans blamed the crash on Medvedev's forum itself, which was held in the Lokomotiv arena, making it impossible for the team to play its first game of the season at home.

Thousands of fans gathered outside the arena Wednesday night to mourn the players and shouts of "Down with the summit!" and "The summit is guilty!" were heard. Forum participants were told Thursday to take off their badges before heading into town.

It was not immediately clear what measures the government could take to cut the number of airlines, many of which are small, regional operations of uncertain financial health. Transport Minister Igor Levitin said Russia has about 130 air carriers, but 85 percent of passengers are carried by just 10 companies.

Medvedev previously has announced plans to take aging Soviet-built planes out of service starting next year. The short- and medium-range Yak-42 has been in service since 1980.

On Thursday morning, hundreds of residents prayed for the victims at the city's Russian Orthodox cathedral, many wearing team scarves as religious headcoverings.

Among the dead were Lokomotiv coach and National Hockey League veteran Brad McCrimmon, a Canadian; assistant coach Alexander Karpovtsev, one of the first Russians to have his name etched on the Stanley Cup as a member of the New York Rangers; and Pavol Demitra, who played for the St. Louis Blues and the Vancouver Canucks and was the Slovakian national team captain.

In the Czech Republic, hundreds of mostly young people honored the victims Thursday at the Old Town Square in the heart of Prague. Wearing Czech national jerseys and carrying Czech flags, they lighted candles around a simple impromptu monument formed by two ice hockey sticks and chanted the names of the three Czech victims. Some signed condolences books for them.

"The winners forever," one entry read.

"It's a tragedy," said Petr Kubalek, 28, from Prague. "That's all I can say. I knew Marek personally. Rachunek was of the top defensemen."

The crash is one of the worst aviation disasters in sports history.

In past plane crashes involving sports teams, 75 Marshall University football players, coaches, fans and airplane crew died in West Virginia on Nov. 14, 1970, while returning from a game. Thirty-six of the dead were players.

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Jim Heintz in Moscow and Karel Janicek in Prague contributed to this story.